Writing & StyleStyle guide

Serial Comma (Oxford Comma)

The “serial comma” and “Oxford comma” name the same list-comma position: immediately before the final conjunction in a series. Microsoft requires it in its house style, but professional writing should follow the relevant publication or organizational style rather than treating the preference as universal grammar.

Quick answer

The serial or Oxford comma comes before the conjunction in a list of three or more items; use it when your governing style requires it.

Key details

Core IssueThe serial comma, also called the Oxford comma, is the comma placed before the conjunction in a list of three or more items; whether it is required is a style-guide choice.
Phrase Roleprofessional-writing and typography guidance
Registerprofessional, technical, and editorial writing

Important caveats

Style Boundary

Other style systems may make a different choice, so consistency with the governing style guide matters.

Further guidance

Definition

The serial or Oxford comma is the comma immediately before the conjunction in a list of three or more items.

Microsoft Style

Microsoft style uses the serial comma in lists of three or more items.

Sources and evidence

Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.

  1. Commas — Microsoft Style Guide (opens in a new tab)Microsoft · Microsoft house-style rule using the serial/Oxford comma before the conjunction in a list of three or more items

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